So, here is my first request for technical help from the amassed knowledge-base on this 'ere forum! I have a 2002 ST4s that is currently in the middle of a major service. I have just measured the valve clearances, using the loaded/unloaded clearance method. The clearances I get are the following:- Horizontal Inlet Left Opening Clearance - 0.152mm Loaded Clearance - 0.19mm Closing Clearance - 0.038mm Right Opening Clearance - 0.038mm Loaded Clearance - 0.051mm Closing Clearance - 0.013mm Horizontal Exhaust Left Opening Clearance - 0.102mm Loaded Clearance - 0.114mm Closing Clearance - 0.012mm Right Opening Clearance - 0.102mm Loaded Clearance - 0.114mm Closing Clearance - 0.012mm Vertical Inlet Left Opening Clearance - 0.076mm Loaded Clearance - 0.102mm Closing Clearance - 0.038mm Right Opening Clearance - 0.076mm Loaded Clearance - 0.254mm Closing Clearance - 0.178mm Vertical Exhaust Left Opening Clearance - 0.152mm Loaded Clearance - 0.19mm Closing Clearance - 0.038mm Right Opening Clearance - 0.102mm Loaded Clearance - 0.152mm Closing Clearance - 0.050mm At the risk of starting an oil thread, or an argument, what is the general feeling about these? Looking at various sources (including the factory manual) would suggest that they are all far too tight, except for 1 opener and 1 closer. Does everyone recommend taking the heads off to re-shim, or is it worth the pain of trying to do them in the bike?
I agree, they are all far to tight except the Horiz left inlet opener and the Vertical left exh opener. The other exhaust clearances are within spec but are on the tight side. I've done many heads and never taken them off the bike. The vertical exhaust can be a bit awkward but once the cams are out there is plenty of room to get at the shims. Also, when you figure in the cost of new head gaskets is it worth it? FWIW in his book "Desmoquattro Maintenance and Modification Guide" LT Snyder recommends setting the openers at .1mm inlet and .15mm exhaust and all the closers at .1mm. Which leaves your Vert Left Exh as the only one that's right.
